I recently added a second user to windows XP. I gave the new user administrative controls and gave the original user limited control. Now, when I go into "user accounts" in the control panel of the administrative account, I get a blank script error. Clicking "yes" or "no" does nothing. Windows site seems to offer no solution. I'm at a loss. Any help/advice is appreciated.

I have never experienced this myself, which makes me believe that this problem has nothing to do with Windows XP itself, but more with other software which might be installed. You give too little information though, so troubleshooting is impossible. Which version of Windows XP are you using, which Service Pack, do you have all the latest hotfixes, anti-virus and anti-spyware software disabled when you try, full desktop screenshot which includes the error message so that we can see at which screen exactly the error message pops up, have you run a full virus and spyware check, et cetera?

Does system restore give the same error?

It sounds like you have a problem with scripting, IE, user registry keys

Reinstall IE

run sfc /scannow

Check registry permissions mentioned in that article talking about blank system restore screen

install scripten.exe

-gosh